The invention relates to a method for broad loom machine weaving an at least two-ply, one-piece airbag.
One-piece woven (OPW) airbags are known which find application in the fabrication of vehicular airbag systems. For inflation of such one-piece woven airbags a gas lance is inserted thereinto. Experience has shown tears materializing in the regions of the airbag in which gas is jetted into the airbag from the gas lance. Gas lances often feature a train of slots, so-called gills, oriented roughly transversely to the gas flow, through which the gas is jetted into the airbag at several locations. The aforementioned tears in the airbag may materialize e.g. because of differences in the design of the inflator, causing it to be more or less aggressive, termed dispersion within and between inflator jets. Tears in the airbag may also be influenced by the positioning of the jet gills relative to the airbag chamber. In addition, airbag tears more frequently occur in borderline situations as regards inflator aggressiveness as well as the ambient temperature at which the airbag is put to use.
The object of the invention is to propose a method for weaving an at least two-ply, one-piece airbag in which the drawbacks as known from prior art, particularly tears in the fabric occuring in the region of the gas flow jetted into an airbag, no longer occur or are at least very greatly reduced.
This object is achieved by a method as it reads from claim 1. The available fabric mass in the one-piece woven airbag as tailorized by the method, now makes it possible to reinforce the airbag fabric individually oriented. Thus, at a high stress location formerly exhibiting airbag tears, a fabric quality is now available of enhanced resistance, achieved among other things by an increase in the thermal capacity in the neuralgic locations of the airbag where namely the jet lances feature their so-called jet gill zone. Now, by increasing the fabric mass to advantage in desired airbag positions in the fabric, a higher strength both mechanically and also thermally is available in preventing tears in the airbag.
In one aspect of the invention a weft yarn is employed in the desired region which as compared to standard yarn has an at least 25% higher dtex. The invention will now be detained with reference to the drawing for a better understanding, in which: